Back then the Hummer was sold by AM General, the original developer and producer of the military version called the Humvee. To this day AM General produces both the military and civilian versions of the Hummer in its Mishawaka, Indiana plant, though it sold the marketing rights for the civilian version to GM in 1999. Since then it's also been contracted to produce the smaller Hummer H2 for General Motors.
AM General will not dismiss any of its workforce because of GM's decision to cancel the H1, but will most likely switch those workers over to production of the military version. The market for the military version seems to be pretty bullish right now, anyway.
[Source: USA Today]